Which energy transformation occurs in the core of a nuclear reactor?
a. nuclear energy to mechanical energy
b. nuclear energy to thermal energy
c. thermal energy to nuclear energy
d. mechanical energy to nuclear energy

The correct answer among the choices given is option B. The energy transformation that occurs in the core of a nuclear reactor is from nuclear energy to thermal energy. In a power plant nuclear fission which involves nuclear energy to heat up water around it. This part is  the core of the process.

If there was no gravity then their would be no downword force on the football to have it return the the grownd, and if there was no friction (mainly air friction) then there would be no opposing force the stop the ball from moving through the air allowing the ball to travle ∞.

It is d, all the other ones say incorrect answer .